The long term objectives of the experiments described in this research proposal are designed to analyze the regulatory effects of lymphokines (IFN-gamma and TNF-alpha) in accelerating or retarding the autoimmune process seen in two animal models of human autoimmune diseases - - nephritis in the (NZBxNZW)F1 mouse, and type I diabetes in the non obese diabetic (NOD) mouse. A series of experiments will probe the possibility of using both with TNF-alpha to achieve more effective prevention/therapy of these two autoimmune diseases. Detailed studies will establish dose, timing, and other characteristics to optimize this therapy and study toxicity sufficiently well to permit a decision as to whether such therapy might be tried in patients. TNF-alpha is most effective in those autoimmune diseases in the mouse in which TNF-alpha production in response to specific stimuli (lipopolysacharride, IFN-gamma) is low in comparison to other mouse strains. Therefore a search will be made for linkage between MHC haplotype and production of low or high levels of TNF-alpha in both the mouse and in patients. Preliminary results indicate that the majority of individuals with HLA-DR2 are low producers of TNF-alpha, while most individuals with HLA-DR3 and 4 are high producers. If linkage studies indicate a link between TNF-alpha response and MHC genotype, genomic cloning of TNF-alpha genes will be undertaken in both high and low producer mouse strains and patients. Genomic clones will be analyzed by restriction mapping in a search for differences between the 5' flanking sequences, intervening sequences, and 3' flanking sequences of TNF-alpha genes from high and low producer genotypes. The results of these studies should lead to better understanding of a number of characteristics of autoimmune disease and to new approaches to therapy.